Rotatable plug lock



April 9, 1963 B. J. MONAHAN ROTATABLE PLUG LOCK April 9, 1963 B. J. MoNAHAN ROTATABLE PLUG Loox 2 Shee1',s sheet 2 Filed De 3, 1959 BYLCUL @Z 2U United States Patent Oiice 3,084,533 Patented Apr. 9, 1953 3,084,533 ROTATABLE PLUG LOCK Brian J. Monahan, Rte. 2, Box 12C, Mundelein, Ill. Filed Dec. 3, w59, Ser. No. 857,124 13 Claims. (Cl. 70-363) This invention relates =to a lock of the rotatable plug yl',l`he major object of the invention is to provide Ia lock such that a plurality of diiierently keyed locks may be opened by a single key. The advantage of the lock is this: with a single key, a user can open several different locks-his car, his house, his tool box-but one who succeeds in picking one of the locks gains no knowledge by which he can quickly pick the second. The advantage of having diiferent locks for various things is retained, but the need for different keys is eliminated. `One key opens all.

A feature of the invention is positioning two pins between two helical springs so that the position of the pins in a pin way depends upon the relative strength of the two springs. By using springs of different lengths in two or more pin ways of the same lock and in different locks, a plurality of locks are provided, Iall of which may nevertheless be opened by the same key.

A second feature of the invention is setting the unlocking position from behind the lock yto iit the key. Thus, a user wants locks for front and back door, garage, tool chest, and cabinet of valuable books. He buys five locks in which the springs controlling thee pins lare not of uniform length. He selects a single key, mounts the locks, adjusts each for opening with the same key from the back of each lock. With a single key he can open any of the locks; yet one who picks one of the locks has no clue to picking any of the rest. In applicants lock, balancing the two opposed springs lin one pin way so as to position the abutting faces in the pins on the turn face between plug and housing, requires a diierent setting from the elements in a second pin way containing different length springs.

Another object of the invention is to enable a user to change his key without changing the locks. Thus, at present, an unauthorized person obtains a key to a lock in an office building. The lock must be changed :and a key to that lock provided. With applicants lock, the user obtains a new key only and ts his lock to that key. The possession of the old key by an unauthorized person is nullied by acquiring only a different key.

These and such other objects of the invention as may hereinafter appear are attained by the embodiment of the invention shown in the `accompanying drawings, wherein:

FIGURE 1 is a sectional View in a vertical plane along the axis of the lock, showing the rotatable plug in locked position;

FIGURE 2 is a cross-sectional view taken on the line 2 2 of FIGURE 1;

FIGURE 3 is a sectional view similar to FIGURE 1, but with a key and an adjusting wrench inserted with the pins in unlocked position;

FIGURE 4 is an end elevation of the outside of the lock;

FIGURE 5 is an end elevation of the inside of the lock;

FIGURE 6 is a section of the lock taken on the line 6-6 of FIGURE 3 showing the lock in unlocked position;

FIGURE 7 is a horizontal section through the lock;

FIGURE 8 is an elevation of a key;

FIGURE 9 is an elevation of the wrench;

FIGURE 10 is a schematic longitudinal section of one pin way illustrating the manner of setting the pins; and

FIGURES 11 and 12 are longitudinal and cross-sectional views of a second embodiment of the invention showing the application of the invention to conventionally mounted pin ways.

Continuing to refer to the drawings, lthe lock consists of a cylindrical barrel or housing H, having an inwardly directed collar 11 which retains a plug P rotatable Iaround the axis of the housing H, and a cylindrical base portion B iixed to the interior of the housing I-I by la screw 10. The plug P has .a transverse slot 12 having a cam surface 14, registering with an opening 15 in lthe housing H. Upon rotation of the plug P, the cam moves into the position shown in FIGURE 6. Applicant has shown in dotted outline in FIGURES 4 and 6 `a bolt 16 which with the lock is mounted on a door 18. In FIGURE 4, the bolt is shown retracted and in FIGURE 6, the bolt is shown advanced to lock the door to the jamb receptacle 20. The mounting of the bolt :16 as =well as the door jamb and jamb receptacle are shown schematically. The bolt will vary with requirements.

Referring to FIGURE l, in the base B are two through holes 22 and 24 on diametrically opposite sides of and parallel to the axis of B. The outer end of each hole is threaded and a set screw 26, having a stem 28 of reduced size and a drive collar 27, is mounted in each. Through each set screw is a hole 30, square in cross section, adapted to receive the square shank 32 of `a wrench 34 having a collar 36.

Through the plug P is a key slot 38, extending the length thereof along its axis. It is of rectangular cross section, see FIGURE 2. In the upper and lower portions of the side walls of the slot 38 are grooves 40, 42, 44 and 46 cut on the same radius as the holes 22 and 24. These grooves terminate short of the front of the plug so that ball bearings 48 and Sii will be retained. The hole 22 and grooves 40 and 42, and the hole 24 and grooves 44 and 46 constitute two pin ways generally designated 1by the numerals 43 and 47.

Slideably disposed in the pin way 43 lare two cylindrical pins 52 and 54 of equal length flanked on each side -by compressible helical springs, i.e., the plug spring 56 and the housing spring 58. Similarly disposed in pin way 47 are two pins 60 and 62 of the same length as pins 52 and 54, flanked on each side by compressible helical springs 64 land 66. Springs 64 and 66 have lengths greater than the lengths of springs 56 and 58. The numeral 68 identitles a at key whose working end has two ball thrust carn surfaces 7i) and 72.

The springs 56 and 64 in the plug P have a minimum length requirement. When in normal uncompressed condition, one or lboth sets yof pins, 52 and 54 or 60 and 62, must intercept the abutting circular faces called the turn face 74 of the plug and the chamber Wall. The springs 58 and 66 must not be sufficiently strong to force the right end of the pins S4 and 62 to the left of the turn face 74, nor should the springs 56 and 64 be strong enough to move the left end of the pins 52 and 60 to the `right of the turn face 74. If a spring intercepts the turn face 74, it might be Ibent by turning the plug. Applicants lock locks with the right hand or housing pins '54 and 62. The springs in ya given pin way, as 56 and 58, may be of equal length and strength for the sake of compactness; however, more facility in the locks is provided by springs of different lengths.

Referring now to schematic FIGURE 10, assume that the ball 48, springs 56 and S8, pins 52 and 54, and set screw 26, touch one another but that no axial interelement Y pressure is exerted. In -order to turn the plug P, the abut- 3. pressure on the plug P, the plug will tu-rn when the abutting faces of pins 52 and 5,4,lie in the plane of the turn face 74. This is not possible where there is a second pin way 47 with pins 6l) and 62, sec FIGURE 1. In this case, one would not know which pin, S2 or 60, was holding the plug.

The setting is done by means of the wrench 34, FIG- URES 9 and 3. Its shank 32 passes through the set screw 2d and the total length of the pin 54 and the shank to the collar 36 equals the length of the passageway through the base B. Referring to FIGURE 10, when the wrench is inserted and no inward pressure exerted, its collar 36 will be spaced from the housing as shown. By turning the wrench until the collar is llush against the housing, with no inward pressure exerted on the wrench 34, the opposed springs 56 and 58k will be holding the abutting surfaces of the pins in the plane of the turn face. There is no need to try turning the plug.

The foregoing describes balancing the two springs to center the pins on the turn face 74, but ignores the key. The key 68 has a ball thrust surface 74) which may be spaced from the shoulder 7l by any distance greater than the distance from the outside face of the plug to the ball 48 land less than the distance that would move the left end of pin 52 to the right of turn face 74 when set screw 2o is retracted llush with the back surface of the base. Assuming that the parts are in position shown in FIGURE 1,0, and the key is inserted, the pins 52 and 54 will move to the right, the expansive strengths of the opposed springs controlling the distance moved. The pin 52 will be moved further into the hole portion of the pin way in the rbase B. By holding the key in position and following the procedure of the next preceding paragraph with the wrench 34, the abutting surfaces of the pins may be moved into the plane of the turn face 7 4.

By selecting a ball thrust surface spaced by a different distance from the shoulder 71, FIGURE 8, -i.e., surface 72, the abutting surfaces of the pins 60 and 62 may be brought into the plane of the turn face.

Thus, applicant provides a plug-type lock which may be quickly set for release position to a wide range of keys. Also, by varying the length of the pins or springs, or strength of the springs, as between pin ways, the same key may be used to open any number of locks, but picking one lock will provide no clew of how to pick the next. Practically, one has the benet of a plurality of different locks which require but one key. Another advantage derives from the ability of the user to readjust the pins when through use, they no longer line up with the turn face. No locksmith is needed. Also, when one loses his keys for present locks, all locks must be changed to be protected from a finder of the keys. But with appli-cants locks, all one need do is fbuy a new and ldilerent key and resetthe locks.

While applicant has shown only two pin ways, one `or more additional pin ways spaced around the axes of the plug P and base B could be provided, and the key slot accordingly modilied. Thus, if there were three pin ways spaced 120 circumferentially apart, the key slot would consist `of three vanes radiating `from la center line, as 80 in FIGURE 8.

Applicants invention of two pins in -a pin way balanced between opposed springs is not limited to ways parallel to the axis of the plug. They may be used in the conventional type of plug lock. In FIGURES 11 and 12, applicant shows the invention applied to the conventional type plug lock. The housing 82 has a below center cylindrical chamber 84 in which is disposed a cylindrical plug. Radiating from the plug are pin lways 86 and 88, which register with pin Ways 90 and `92 in the housing 82. The pin ways 86 and 88 intersect at their lower ends a key slot and each pin way contains :in order a ball `89, helical spring 91, pins 94 and 96, helical spring 98, and set screw E100 threaded in the outer end of the pin Way in the housing H. The .insertion of the key followed by the setting of the pins follows the procedure heretofore described.

The turn face is between the cylindrical surfaces of the plug and housing.

Referring to FIGURE l, applicant may terminate the key slot at the dotted line 53, the portion to the right of the `dotted line becoming a part of the plug itself. This Vwill deter one trying to pick the lock Iby inserting a wire which reaches the pins 52, 54.

This construction will have use where the door is thin and it is desirable to have the long pin way parallel to the surface of the door. The preferred construction of FIGURES l to l0 requires a thicker door, but the preferred embodiment permits of'a much greater variation in keys.

The keys for either Vembodiment may carry longitudinal grooves to t matching 'wales in a slot, as in standard keys.

Having thus described his invention, applicant claims:

l. A tumbler lock comprising a housing, a cylindrical chamber in said housing, a cylindrical plug rotatable in the chamber, means for .actuating a bolt associated with the plug, a pin way in the housing, a pin way in the plug al-ignable with the pin way in the housing, a pin in each pin way, expansion means in each pin way urging the associated pins toward each other, and a key slot in the plug intersecting fthe plug pin way.

2. The tumbler lock of claim l together with means associated with one pin way for varying the tension on the expansion means.

3. A lock comprising, a housing having one smooth surface, a member movable with respect to the housing and having a complementary smooth surface in contacting engagement with that of the housing, a straight pin way extending through the housing and into the movable member, a pair of abutting .pins slideably positioned in the pin way, a compression spring in the pin way of the housing engaging one of the pins and urging the engaged pin toward the other of said pins, a second compression spring in the pin way of the movable member engaging the other of said pins and urging the .other of said pins toward the first mentioned compression spring, said two springs opposing each other to position the .pins in a position locking .the movable member to the housing in one direction when the springs are in balance and in their maximum extended attitude within the housing and the movable member, an externally accessible setscrew in one end of the pin way, and a key slot intersecting the other end of the pin way.

4. In combination with the lock of c-laim 3, a wrench comprising a stem having a collar, said collar being spaced from the end of the stern by a distance equal to the length of the pin way in the housing less the length of the nearest pin in the pin way said stern being engageable with the setscrew to move .the setscrew to adjust the ldis/tance between opposed ends of the springs.

5. In combination with the lock of claim 3, a wrench comprising a stern having a collar, said collar being spaced from the end of the stem by a distance equal to the length of the pin way of the housing less the length of the nearest pin in the pin way, together with an axial passageway through the set screw, and means on the stem of the wrench for turning the set screw when the stem is through said passageway and -in the pin way.

6. A lock comprising a housing, a cylindrical chamber therein, a cylindrical plug rotatable Iin said chamber, a turn face :formed by contacting walls of the chamber and plug, a key slot extending .through one end ySurface and into the plug and parallel to its axis, a pin way inthe plug having an opening into the key slot and extending across the turn face and through the housing, two end-abutting pins slideable in the pin way, a compression spring in the plug portion of the pin way biasing said pins in one direction and a compression spring in the housing portion of the pin way biasing the pins in the opposed direction, said spring in the plug being in both the pin way and the key slot, and setting means in the pin way accessible from the outside of the housing and engaging the housing spring for varying the tension on the housing spring whereby the vabutting faces of the pins may be brought into register with the turn face.

7. The ylock of claim 6 wherein the setting means comprises a set screw threaded into the outer housing end of the pin way.

8. The lock of claim i6 wherein the turn face is between the inner end of the cylindrical plug and Ithe adjacent wall of the chamber.

9. The lock of claim f6 wherein the turn face is between the cylindrical surfaces of the plug and chamber.

10. In combination with the lock of claim -6 which has a setting means comprising a set screw threaded into the outer housing end of .the pin way, a wrench comprising a stem having a collar, said `collar being spaced from an end of the stem by a distance equal to the length of the pin way in the housing less the length of @the nearest pin in the pin Way, an axial passageway through the set screw, and means on the stem of .the wrench `for turning the set screw when the stern extends through the axial passageway and in the pin way.

11. The lock of claim 6 together with a second pin way parallel to the rst with like pins, springs and setting 4means therein.

12. The lock of claim 1:1 wherein the springs in one pin way have different compressive resistance.

l13. The lock of claim 111 wherein the expansive strength of the springs in one pin way exceeds the expansive strength of the springs in the other pin way.

References Cited in the le of this patent UNITED STATES PATENTS 1,043,131 Nielson Nov. 5, 1912 1,204,753 Fourcher NOV. 14, 1916 :1,333,974 Gordon Mar. 16, 1920 1,494,765 yBarrett May 20', 1924 1,707,922 Pepper Apr. 2, 1929 2,616,740 Thousand Nov. 4, 19152 2,621,510 Rarnhoj Dec. 16, 1952 2,687,638 Abernathy Aug. 31, 19'54 FOREGN PATENTS 540,068 France Apr. 11, 1922 

1. A TUMBLER LOCK COMPRISING A HOUSING, A CYLINDRICAL CHAMBER IN SAID HOUSING, A CYLINDRICAL PLUG ROTATABLE IN THE CHAMBER, MEANS FOR ACTUATING A BOLT ASSOCIATED WITH THE PLUG, A PIN WAY IN THE HOUSING, A PIN WAY IN THE PLUG ALIGNABLE WITH THE PIN WAY IN THE HOUSING, A PIN IN EACH PIN WAY, EXPANSION MEANS IN EACH PIN WAY URGING THE ASSOCIATED PINS TOWARD EACH OTHER, AND A KEY SLOT IN THE PLUG INTERSECTING THE PLUG PIN WAY. 